The field of the invention is wattmeters and watt-hour meters, and more specifically, watt-hour meters constructed from solid state electronic components.
There are a number of known wattmeters and watt-hour meters constructed of solid state electronic components. Such meters sense the magnitude of the voltage (E) and the magnitude of the current (I) and multiply them together to provide a signal proportional to their product (EI). Typically, however, the power factor (cos .theta.) is not taken into consideration in such meters and is instead assumed to be one. Such is often not the case, particularly in industrial environments where large numbers of reactive load devices are employed. The accuracy of these prior meters thus leaves much to be desired.
A watts transducer constructed of solid state devices which does take into consideration the power factor is disclosed in U.S. Pat. No. 3,794,917.